流感最新消息N°525

Global Respiratory Virus Activity Weekly Update No. 525 Summarizing data through Week 17, ending 27 April 2025 Summary Influenza •In the Northern hemisphere, influenza positivity continued to decline or remained stable in most countries. Influenza positivity remained elevated in Central America and theCaribbean and Tropical South America (predominantly A(H1N1)pdm09), in Western Africa (predominantly A(H1N1)pdm09), Eastern Africa (predominantly A viruses),in Europe and Western Asia (predominantly A(H3N2) and B), in Southern Asia (predominantly A(H3N2)), Eastern Asia (predominantly A(H1N1)pdm09 and B) andSouth-East Asia (predominantly A viruses).•In the Southern hemisphere, positivity remained stable with small increases in Temperate South America. Influenza positivity was elevated in a few countries in Tropical and Temperate South America and Oceania (predominantly A(H1N1)pdm09), Southern Africa (predominantly A(H3N2)), Eastern Africa and South-East Asia (predominantlyInfluenza A Viruses) and Oceania (predominantly A(H1N1)pdm09). SARS-CoV-2 •Globally, positivity continued to remain low across reporting countries except for single countries in Central America and the Caribbean, South-West Europe and WesternAsia. Additional information DataonrespiratoryvirussurveillanceareprovidedtoWHOthroughparticipa-tion or collaboration with the Global Influenza Surveillance and Response System (GISRS).Countries, areas, and territories (CATs) use a variety of approaches to monitor respiratoryvirus activity and data in this report may vary from surveillance reports posted elsewhere.Data in this report include virologic results from sentinel surveillance and other typesof systematically conducted virologic surveillance, depending on the CAT. Differencesin surveillance approaches limit comparison of percent positivity between CATs.Thesource of surveillance used in this report was determined in collaboration with WHORegional Offices and the reporting CAT. Analyses stratified by source of surveillance isavailable through RespiMart. Additional information on COVID-19 is reported on theWHO COVID-19 dashboard. TheproportionofspecimenstestingpositiveforinfluenzaorSARS-CoV-2wassmoothed over a 3-week period among CATs who reported testing at least 10 specimensfor 2 weeks of the 3-week period. The change in smoothed proportion of specimens testingpositive for each virus was calculated as the absolute difference from the smoothed valueduring the prior reporting week. ActivityissummarizedbygeographicalgroupingsofCATs.Thesegroupingswere used for their geographical description and do not imply similarity of respiratoryvirus transmission within each group. More information about the geographical groupingscan be found here. Specimens testing positive for influenza, by virus type and subtype Regional Reports Latest WHO regional surveillance reports: African | Americas | Eastern Mediterranean | European | South-East Asia | Western Pacific Summary was generated by the WHO Global Influenza Programme based on data last updated in RespiMart on May 04 2025 11:52:15 PM UTC